Our research project is directed towards the study of membrane proteins of human erythrocytes and lymphocytes. Membrane proteins are solubilized, extracted and purified; they are analyzed by biochemical and immunologic methods for further characterization and the delineation of inherited variations. The study is concerned in particular, with the sialoglycoproteins of human red cell membranes and the phytohemagglutinin receptor of lymphocytes. The study is directed towards a comparative analysis of membrane proteins and receptors in healthy persons with those from patients with hereditary diseases. In particular, erythrocytes from patients with hereditary spherocytosis and elliptocytosis and lymphocytes from patients with primary immunedeficiencies will be studied.